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Comparing libecb/ecb.h (file contents):
Revision 1.1 by root, Thu May 26 16:41:12 2011 UTC vs.
Revision 1.94 by root, Tue May 29 21:03:20 2012 UTC

1/* 1/*
2 * libecb 2 * libecb - http://software.schmorp.de/pkg/libecb
3 * 3 *
4 * Copyright (c) 2011 Marc Alexander Lehmann 4 * Copyright (©) 2009-2012 Marc Alexander Lehmann <libecb@schmorp.de>
5 * Copyright (©) 2011 Emanuele Giaquinta
5 * All rights reserved. 6 * All rights reserved.
6 * 7 *
7 * Redistribution and use in source and binary forms, with or without modifica- 8 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met: 9 * tion, are permitted provided that the following conditions are met:
9 * 10 *
… …
27 */ 28 */
28 29
29#ifndef ECB_H 30#ifndef ECB_H
30#define ECB_H 31#define ECB_H
31 32
33/* 16 bits major, 16 bits minor */
34#define ECB_VERSION 0x00010001
35
36#ifdef _WIN32
37 typedef signed char int8_t;
38 typedef unsigned char uint8_t;
39 typedef signed short int16_t;
40 typedef unsigned short uint16_t;
41 typedef signed int int32_t;
42 typedef unsigned int uint32_t;
43 #if __GNUC__
44 typedef signed long long int64_t;
45 typedef unsigned long long uint64_t;
46 #else /* _MSC_VER || __BORLANDC__ */
47 typedef signed __int64 int64_t;
48 typedef unsigned __int64 uint64_t;
49 #endif
50 #ifdef _WIN64
51 #define ECB_PTRSIZE 8
52 typedef uint64_t uintptr_t;
53 typedef int64_t intptr_t;
54 #else
55 #define ECB_PTRSIZE 4
56 typedef uint32_t uintptr_t;
57 typedef int32_t intptr_t;
58 #endif
59 typedef intptr_t ptrdiff_t;
60#else
61 #include <inttypes.h>
62 #if UINTMAX_MAX > 0xffffffffU
63 #define ECB_PTRSIZE 8
64 #else
65 #define ECB_PTRSIZE 4
66 #endif
67#endif
68
69/* many compilers define _GNUC_ to some versions but then only implement
70 * what their idiot authors think are the "more important" extensions,
71 * causing enormous grief in return for some better fake benchmark numbers.
72 * or so.
73 * we try to detect these and simply assume they are not gcc - if they have
74 * an issue with that they should have done it right in the first place.
75 */
76#ifndef ECB_GCC_VERSION
77 #if !defined __GNUC_MINOR__ || defined __INTEL_COMPILER || defined __SUNPRO_C || defined __SUNPRO_CC || defined __llvm__ || defined __clang__
78 #define ECB_GCC_VERSION(major,minor) 0
79 #else
32#define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor))) 80 #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
81 #endif
82#endif
83
84#define ECB_C (__STDC__+0) /* this assumes that __STDC__ is either empty or a number */
85#define ECB_C99 (__STDC_VERSION__ >= 199901L)
86#define ECB_C11 (__STDC_VERSION__ >= 201112L)
87#define ECB_CPP (__cplusplus+0)
88#define ECB_CPP98 (__cplusplus >= 199711L)
89#define ECB_CPP11 (__cplusplus >= 201103L)
90
91/*****************************************************************************/
92
93/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */
94/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */
95
96#if ECB_NO_THREADS
97# define ECB_NO_SMP 1
98#endif
99
100#if ECB_NO_SMP
101 #define ECB_MEMORY_FENCE do { } while (0)
102#endif
103
104#ifndef ECB_MEMORY_FENCE
105 #if ECB_GCC_VERSION(2,5) || defined __INTEL_COMPILER || (__llvm__ && __GNUC__) || __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
106 #if __i386 || __i386__
107 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
108 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
109 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
110 #elif __amd64 || __amd64__ || __x86_64 || __x86_64__
111 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
112 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
113 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
114 #elif __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__
115 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
116 #elif defined __ARM_ARCH_6__ || defined __ARM_ARCH_6J__ \
117 || defined __ARM_ARCH_6K__ || defined __ARM_ARCH_6ZK__
118 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mcr p15,0,%0,c7,c10,5" : : "r" (0) : "memory")
119 #elif defined __ARM_ARCH_7__ || defined __ARM_ARCH_7A__ \
120 || defined __ARM_ARCH_7M__ || defined __ARM_ARCH_7R__
121 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb" : : : "memory")
122 #elif __sparc || __sparc__
123 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad | #StoreStore | #StoreLoad" : : : "memory")
124 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad" : : : "memory")
125 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("membar #LoadStore | #StoreStore")
126 #elif defined __s390__ || defined __s390x__
127 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("bcr 15,0" : : : "memory")
128 #elif defined __mips__
129 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
130 #elif defined __alpha__
131 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mb" : : : "memory")
132 #elif defined __hppa__
133 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
134 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
135 #elif defined __ia64__
136 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mf" : : : "memory")
137 #endif
138 #endif
139#endif
140
141#ifndef ECB_MEMORY_FENCE
142 #if ECB_GCC_VERSION(4,7)
143 /* see comment below about the C11 memory model. in short - avoid */
144 #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST)
145 #elif defined __clang && __has_feature (cxx_atomic)
146 /* see above */
147 #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)
148 #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__
149 #define ECB_MEMORY_FENCE __sync_synchronize ()
150 /*#define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); }) */
151 /*#define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); }) */
152 #elif _MSC_VER >= 1400 /* VC++ 2005 */
153 #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
154 #define ECB_MEMORY_FENCE _ReadWriteBarrier ()
155 #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
156 #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
157 #elif defined _WIN32
158 #include <WinNT.h>
159 #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
160 #elif __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
161 #include <mbarrier.h>
162 #define ECB_MEMORY_FENCE __machine_rw_barrier ()
163 #define ECB_MEMORY_FENCE_ACQUIRE __machine_r_barrier ()
164 #define ECB_MEMORY_FENCE_RELEASE __machine_w_barrier ()
165 #elif __xlC__
166 #define ECB_MEMORY_FENCE __sync ()
167 #endif
168#endif
169
170#ifndef ECB_MEMORY_FENCE
171 #if ECB_C11 && !defined __STDC_NO_ATOMICS__
172 /* we assume that these memory fences work on all variables/all memory accesses, */
173 /* not just C11 atomics and atomic accesses */
174 #include <stdatomic.h>
175 /* unfortunately, the C11 memory model seems to be very limited, and unable to express */
176 /* simple barrier semantics. That means we need to take out thor's hammer. */
177 #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst)
178 #endif
179 #endif
180#endif
181
182#ifndef ECB_MEMORY_FENCE
183 #if !ECB_AVOID_PTHREADS
184 /*
185 * if you get undefined symbol references to pthread_mutex_lock,
186 * or failure to find pthread.h, then you should implement
187 * the ECB_MEMORY_FENCE operations for your cpu/compiler
188 * OR provide pthread.h and link against the posix thread library
189 * of your system.
190 */
191 #include <pthread.h>
192 #define ECB_NEEDS_PTHREADS 1
193 #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1
194
195 static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
196 #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
197 #endif
198#endif
199
200#if !defined ECB_MEMORY_FENCE_ACQUIRE && defined ECB_MEMORY_FENCE
201 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
202#endif
203
204#if !defined ECB_MEMORY_FENCE_RELEASE && defined ECB_MEMORY_FENCE
205 #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
206#endif
207
208/*****************************************************************************/
209
210#if __cplusplus
211 #define ecb_inline static inline
212#elif ECB_GCC_VERSION(2,5)
213 #define ecb_inline static __inline__
214#elif ECB_C99
215 #define ecb_inline static inline
216#else
217 #define ecb_inline static
218#endif
219
220#if ECB_GCC_VERSION(3,3)
221 #define ecb_restrict __restrict__
222#elif ECB_C99
223 #define ecb_restrict restrict
224#else
225 #define ecb_restrict
226#endif
227
228typedef int ecb_bool;
229
230#define ECB_CONCAT_(a, b) a ## b
231#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
232#define ECB_STRINGIFY_(a) # a
233#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
234
235#define ecb_function_ ecb_inline
33 236
34#if ECB_GCC_VERSION(3,1) 237#if ECB_GCC_VERSION(3,1)
35# define ecb_attribute(attrlist) __attribute__(attrlist) 238 #define ecb_attribute(attrlist) __attribute__(attrlist)
36# define ecb_is_constant(c) __builtin_constant_p (c) 239 #define ecb_is_constant(expr) __builtin_constant_p (expr)
37# define ecb_expect(expr,value) __builtin_expect ((expr),(value)) 240 #define ecb_expect(expr,value) __builtin_expect ((expr),(value))
38# define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality) 241 #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
39#else 242#else
40# define ecb_attribute(attrlist) 243 #define ecb_attribute(attrlist)
41# define ecb_is_constant(c) 0 244 #define ecb_is_constant(expr) 0
42# define ecb_expect(expr,value) (expr) 245 #define ecb_expect(expr,value) (expr)
43# define ecb_prefetch(addr,rw,locality) 246 #define ecb_prefetch(addr,rw,locality)
44#endif 247#endif
45 248
249/* no emulation for ecb_decltype */
46#if ECB_GCC_VERSION(4,5) 250#if ECB_GCC_VERSION(4,5)
47# define ecb_decltype(x) __decltype(x) 251 #define ecb_decltype(x) __decltype(x)
48#elif ECB_GCC_VERSION(3,0) 252#elif ECB_GCC_VERSION(3,0)
49# define ecb_decltype(x) typeof(x) 253 #define ecb_decltype(x) __typeof(x)
50#endif 254#endif
51 255
52#define ecb_noinline ecb_attribute ((noinline)) 256#define ecb_noinline ecb_attribute ((__noinline__))
53#define ecb_noreturn ecb_attribute ((noreturn))
54#define ecb_unused ecb_attribute ((unused)) 257#define ecb_unused ecb_attribute ((__unused__))
55#define ecb_const ecb_attribute ((const)) 258#define ecb_const ecb_attribute ((__const__))
56#define ecb_pure ecb_attribute ((pure)) 259#define ecb_pure ecb_attribute ((__pure__))
260
261#if ECB_C11
262 #define ecb_noreturn _Noreturn
263#else
264 #define ecb_noreturn ecb_attribute ((__noreturn__))
265#endif
266
267#if ECB_GCC_VERSION(4,3)
268 #define ecb_artificial ecb_attribute ((__artificial__))
57#define ecb_hot ecb_attribute ((hot)) // 4.3 269 #define ecb_hot ecb_attribute ((__hot__))
58#define ecb_cold ecb_attribute ((cold)) // 4.3 270 #define ecb_cold ecb_attribute ((__cold__))
271#else
272 #define ecb_artificial
273 #define ecb_hot
274 #define ecb_cold
275#endif
276
277/* put around conditional expressions if you are very sure that the */
278/* expression is mostly true or mostly false. note that these return */
279/* booleans, not the expression. */
280#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
281#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
282/* for compatibility to the rest of the world */
283#define ecb_likely(expr) ecb_expect_true (expr)
284#define ecb_unlikely(expr) ecb_expect_false (expr)
285
286/* count trailing zero bits and count # of one bits */
287#if ECB_GCC_VERSION(3,4)
288 /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
289 #define ecb_ld32(x) (__builtin_clz (x) ^ 31)
290 #define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
291 #define ecb_ctz32(x) __builtin_ctz (x)
292 #define ecb_ctz64(x) __builtin_ctzll (x)
293 #define ecb_popcount32(x) __builtin_popcount (x)
294 /* no popcountll */
295#else
296 ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
297 ecb_function_ int
298 ecb_ctz32 (uint32_t x)
299 {
300 int r = 0;
301
302 x &= ~x + 1; /* this isolates the lowest bit */
303
304#if ECB_branchless_on_i386
305 r += !!(x & 0xaaaaaaaa) << 0;
306 r += !!(x & 0xcccccccc) << 1;
307 r += !!(x & 0xf0f0f0f0) << 2;
308 r += !!(x & 0xff00ff00) << 3;
309 r += !!(x & 0xffff0000) << 4;
310#else
311 if (x & 0xaaaaaaaa) r += 1;
312 if (x & 0xcccccccc) r += 2;
313 if (x & 0xf0f0f0f0) r += 4;
314 if (x & 0xff00ff00) r += 8;
315 if (x & 0xffff0000) r += 16;
316#endif
317
318 return r;
319 }
320
321 ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
322 ecb_function_ int
323 ecb_ctz64 (uint64_t x)
324 {
325 int shift = x & 0xffffffffU ? 0 : 32;
326 return ecb_ctz32 (x >> shift) + shift;
327 }
328
329 ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
330 ecb_function_ int
331 ecb_popcount32 (uint32_t x)
332 {
333 x -= (x >> 1) & 0x55555555;
334 x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
335 x = ((x >> 4) + x) & 0x0f0f0f0f;
336 x *= 0x01010101;
337
338 return x >> 24;
339 }
340
341 ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
342 ecb_function_ int ecb_ld32 (uint32_t x)
343 {
344 int r = 0;
345
346 if (x >> 16) { x >>= 16; r += 16; }
347 if (x >> 8) { x >>= 8; r += 8; }
348 if (x >> 4) { x >>= 4; r += 4; }
349 if (x >> 2) { x >>= 2; r += 2; }
350 if (x >> 1) { r += 1; }
351
352 return r;
353 }
354
355 ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
356 ecb_function_ int ecb_ld64 (uint64_t x)
357 {
358 int r = 0;
359
360 if (x >> 32) { x >>= 32; r += 32; }
361
362 return r + ecb_ld32 (x);
363 }
364#endif
365
366ecb_function_ ecb_bool ecb_is_pot32 (uint32_t x) ecb_const;
367ecb_function_ ecb_bool ecb_is_pot32 (uint32_t x) { return !(x & (x - 1)); }
368ecb_function_ ecb_bool ecb_is_pot64 (uint64_t x) ecb_const;
369ecb_function_ ecb_bool ecb_is_pot64 (uint64_t x) { return !(x & (x - 1)); }
370
371ecb_function_ uint8_t ecb_bitrev8 (uint8_t x) ecb_const;
372ecb_function_ uint8_t ecb_bitrev8 (uint8_t x)
373{
374 return ( (x * 0x0802U & 0x22110U)
375 | (x * 0x8020U & 0x88440U)) * 0x10101U >> 16;
376}
377
378ecb_function_ uint16_t ecb_bitrev16 (uint16_t x) ecb_const;
379ecb_function_ uint16_t ecb_bitrev16 (uint16_t x)
380{
381 x = ((x >> 1) & 0x5555) | ((x & 0x5555) << 1);
382 x = ((x >> 2) & 0x3333) | ((x & 0x3333) << 2);
383 x = ((x >> 4) & 0x0f0f) | ((x & 0x0f0f) << 4);
384 x = ( x >> 8 ) | ( x << 8);
385
386 return x;
387}
388
389ecb_function_ uint32_t ecb_bitrev32 (uint32_t x) ecb_const;
390ecb_function_ uint32_t ecb_bitrev32 (uint32_t x)
391{
392 x = ((x >> 1) & 0x55555555) | ((x & 0x55555555) << 1);
393 x = ((x >> 2) & 0x33333333) | ((x & 0x33333333) << 2);
394 x = ((x >> 4) & 0x0f0f0f0f) | ((x & 0x0f0f0f0f) << 4);
395 x = ((x >> 8) & 0x00ff00ff) | ((x & 0x00ff00ff) << 8);
396 x = ( x >> 16 ) | ( x << 16);
397
398 return x;
399}
400
401/* popcount64 is only available on 64 bit cpus as gcc builtin */
402/* so for this version we are lazy */
403ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
404ecb_function_ int
405ecb_popcount64 (uint64_t x)
406{
407 return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
408}
409
410ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) ecb_const;
411ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) ecb_const;
412ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
413ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
414ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
415ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
416ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
417ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
418
419ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
420ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
421ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
422ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
423ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
424ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
425ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
426ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }
427
428#if ECB_GCC_VERSION(4,3)
429 #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
430 #define ecb_bswap32(x) __builtin_bswap32 (x)
431 #define ecb_bswap64(x) __builtin_bswap64 (x)
432#else
433 ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
434 ecb_function_ uint16_t
435 ecb_bswap16 (uint16_t x)
436 {
437 return ecb_rotl16 (x, 8);
438 }
439
440 ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
441 ecb_function_ uint32_t
442 ecb_bswap32 (uint32_t x)
443 {
444 return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
445 }
446
447 ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
448 ecb_function_ uint64_t
449 ecb_bswap64 (uint64_t x)
450 {
451 return (((uint64_t)ecb_bswap32 (x)) << 32) | ecb_bswap32 (x >> 32);
452 }
453#endif
59 454
60#if ECB_GCC_VERSION(4,5) 455#if ECB_GCC_VERSION(4,5)
61# define ecb_unreachable() __builtin_unreachable () 456 #define ecb_unreachable() __builtin_unreachable ()
62#else 457#else
63 // this seems to work fine, but gcc always emits a warning for it :/ 458 /* this seems to work fine, but gcc always emits a warning for it :/ */
64 static inline void ecb_unreachable () ecb_attribute ((noreturn)); 459 ecb_inline void ecb_unreachable (void) ecb_noreturn;
65 static inline void ecb_unreachable () { } 460 ecb_inline void ecb_unreachable (void) { }
66#endif 461#endif
67 462
68// put into ifs if you are very sure that the expression
69// is mostly true or mosty false. note that these return
70// booleans, not the expression.
71#define ecb_expect_false(expr) ecb_expect ((expr) ? 1 : 0, 0)
72#define ecb_expect_true(expr) ecb_expect ((expr) ? 1 : 0, 1)
73
74// try to tell the compiler that some condition is definitely true 463/* try to tell the compiler that some condition is definitely true */
75#define ecb_assume(cond) do { if (!(cond)) unreachable (); } while (0) 464#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
76 465
77// count trailing zero bits and count # of one bits 466ecb_inline unsigned char ecb_byteorder_helper (void) ecb_const;
78#if ECB_GCC_VERSION(3,4) 467ecb_inline unsigned char
79static inline int ecb_ctz (unsigned int x) { return __builtin_ctz (x); } 468ecb_byteorder_helper (void)
80static inline int ecb_popcount (unsigned int x) { return __builtin_popcount (x); }
81#else
82static int ecb_ctz (unsigned int x) ecb_const
83{ 469{
84 int r = 0; 470 const uint32_t u = 0x11223344;
85 471 return *(unsigned char *)&u;
86 x &= -x; // this isolates the lowest bit
87
88 if (x & 0xaaaaaaaa) r += 1;
89 if (x & 0xcccccccc) r += 2;
90 if (x & 0xf0f0f0f0) r += 4;
91 if (x & 0xff00ff00) r += 8;
92 if (x & 0xffff0000) r += 16;
93
94 return r;
95} 472}
96 473
97static int ecb_popcount (unsigned int x) ecb_const 474ecb_inline ecb_bool ecb_big_endian (void) ecb_const;
98{ 475ecb_inline ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
99 x -= (x >> 1) & 0x55555555; 476ecb_inline ecb_bool ecb_little_endian (void) ecb_const;
100 x = ((x >> 2) & 0x33333333) + (x & 0x33333333); 477ecb_inline ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
101 x = ((x >> 4) + x) & 0x0f0f0f0f;
102 x *= 0x01010101;
103 478
104 return x >> 24; 479#if ECB_GCC_VERSION(3,0) || ECB_C99
105} 480 #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
481#else
482 #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
106#endif 483#endif
107 484
485#if __cplusplus
486 template<typename T>
487 static inline T ecb_div_rd (T val, T div)
488 {
489 return val < 0 ? - ((-val + div - 1) / div) : (val ) / div;
490 }
491 template<typename T>
492 static inline T ecb_div_ru (T val, T div)
493 {
494 return val < 0 ? - ((-val ) / div) : (val + div - 1) / div;
495 }
496#else
497 #define ecb_div_rd(val,div) ((val) < 0 ? - ((-(val) + (div) - 1) / (div)) : ((val) ) / (div))
498 #define ecb_div_ru(val,div) ((val) < 0 ? - ((-(val) ) / (div)) : ((val) + (div) - 1) / (div))
108#endif 499#endif
109 500
501#if ecb_cplusplus_does_not_suck
502 /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
503 template<typename T, int N>
504 static inline int ecb_array_length (const T (&arr)[N])
505 {
506 return N;
507 }
508#else
509 #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
510#endif
511
512#endif
513

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